JPH0218329A - Formation of thin ferrite film - Google Patents

Abstract

PURPOSE:To easily obtain a thin ferrite film having excellent homogeneity on a heat resistant base body for forming a thin film of a soln. mixture contg. prescribed plural compds. on said base body, then drying the thin film and calcining the same in an oxidative atmosphere. CONSTITUTION:The soln. mixture contg. the compds. respectively selected from a group A, group B, group D, and group E or group A, group C, group D, and group E among the separately described group A, group B, group C, group D, and group E is prepd. After this soln. mixture is coated on the heat resistant base body which withstands the calcination temp. to be described afterward, the coating is dried to form the thin gel film consisting of the above-mentioned compds. This thin gel film is calcined together with the base body in the oxidative atmosphere to decompose and evaporate away the org. components and to oxidize the compds. of the respective groups A, B, C, by which the spinel type thin film is obtd. The above-mentioned calcination atmosphere is specified to O2 of 20-100% concn. The heating up rate is preferably specified to 1-1,000 deg.C/min and the calcination temp. to 350-1,200 deg.C.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a magnetic recording medium, a magneto-optical recording medium, a magnetic head, a magneto-optical element, a microwave element,
The present invention relates to a method for forming a ferrite thin film that acts as a magnetostrictive element, a magnetic@acoustic element, etc.

(Prior art) There are various methods for forming ferrite thin films, such as physical vapor deposition (PVD), chemical vapor deposition (CVD), and sputtering. There are problems in that it is not only difficult to adjust, but also requires expensive equipment. Therefore, a wet film forming method using a sol-gel method is being investigated.

For example, Ceramics Association, 1986 Annual Conference Lecture Proceedings, No. 8
27 (1987) describes a method for forming a ferrite thin film by a sol-gel method using inorganic salts such as nitrates and chlorides of various metals as raw materials. However, this method has the problem that it is difficult to obtain a homogeneity higher than that of particles of an inorganic salt or its hydrate, and it is difficult to form a single phase.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems of the conventional methods and to provide a method for forming a highly homogeneous ferrite thin film on a substrate.

(Means for Solving the Problems) In order to achieve the above object, in this invention, among the compounds of the following groups A, Bg, I, D and 1, group A, group B, group D and El Alternatively, a step of preparing a mixed solution containing a compound selected from Group A, Group 0, Group D and Group 1, and Group A: Fe, methoxide, ethoxide, propoxide, butoxide, methoxyethoxide or Ethoxyethoxide B & ¥: Co, N 1SZn, Mn, Cu, LMq, A
I, Cr, ■, Sb, MOl"li, 3n, methoxide, ethoxide, propoxide, butoxide, methoxyethoxide or ethoxy 1 to oxide Group C: [3a, 3r, Pb, methoxide, ethoxide, propoxide, Butoxide, methoxy ethoxide or ethoxy ethoxide Group D: monoethanolamine, jetanolamine, triethanolamine, 7) 2-propanolamine, di-2-propanolamine, acetylacetone, ethylene glycol, diethylene glycol, propylene glycol, Propylene glycol group 1: methanol, ethanol, propatool, butanol, methoxyethanol, ethoxyethanol A step of forming a thin film of the above mixed solution on a heat-resistant substrate, a step of drying the above thin film, and a step of oxidizing the above dried thin film. Provided is a method for forming a ferrite thin film, comprising the steps of: converting the method into a ferrite thin film by firing in a neutral atmosphere.

This invention relates to the above-mentioned groups A, B, 0, D and 1.
Among the compounds of the group, when using a compound selected from group A, group B, group D, and group 1, and when using a compound selected from group A, group 0, and group D,
Compounds selected from each group and group 1 may be used. In the following, for convenience, the former method will be referred to as the first method, and the latter method will be referred to as the second method. However, regarding the compounds of Group B and Group 0, two or more types can be used simultaneously.

Now, according to the first method, a spinel type ferrite represented by the following general formula can be obtained.

Fe2O4 However, M: B group metal elements (Fe, Co, Ni
, Zn, Mn, Cu, "at least one of Mg, AI, Cr, V, Sb, MO, Ti, 3n)". That is, for example, when M is Co, C0Fe2O
4 is obtained, and in the case of N1, N i Fe2O4 is 1q
In the case of Mn and 7-n, Mnx7 of Mn-Zn system
1q of nl-x Fe204 mixed crystal ferrite is produced.

However, with this first method, it is also possible to obtain a ferrite such as COFeC0Fe2-x in which trivalent Fe is partially substituted.

Further, according to the second method, a magnetoblanbite type ferrite represented by the following general formula can be obtained.

M Fe 12019 However, M: 0 group metal element (at least one of Ba, Sr, and Pb) In addition, in the case of the second method, co, Ni, Mn, z
n, ca, Tr, In, Nb, La, Ce, pr, 3m
It is also possible to denature it by adding Ba[
Ferrites such as C12-2 and C0xTlxO19 are obtained.

Hereinafter, each step of the first method will be explained in more detail.

Preparation process of mixed solution: In the first method, first, the following A, B, D, E
Prepare a mixed solution containing a compound selected from @Sen.

Group A: 2 Fe, methoxide, ethoxide, propoxide, butoxide, methoxyethoxide or ethoxyethoxide Group B: Co, Ni, Zn, Mn, CIJ, Li, MO,
AI, Cr, ■, 3b, MO.

Hi, 3n, methoxide, ethoxide, propoxide, butoxide, methoxyethoxide or ethoxyethoxide Group D: monoethanolamine, jetanolamine, triethanolamine, 7) 2-propanolamine, di-2-propanolamine , acetylacetone, ■ tyrene glycol, diethylene glycol, propylene glycol, dipropylene glycol Group E: methanol, ethanol, propatool, butanol, methoxyethanol, ethoxyethanol The propoxides in each of the above groups A and B include coprobanol, 2-propoxy It can be any of the following. Moreover, butoxide may be any of 1-butoxide, 2-butoxide, isobutoxide, and ↑-butoxide. Furthermore, the property tools of group E include coprobanol,
2-Property tools may be used. Furthermore, butanol may be any of ]-butanol, 2-butanol, isobutanol, and t-butanol.

The compounds of the above groups A and B are the main components of ferrite.

Further, the compounds of group 0 suppress the precipitation of compounds of groups A and B as fine particulate hydroxides and oxides due to hydrolysis in each step up to firing.

Furthermore, the compounds of Group E act as solvents.

One type is selected and used from each group A, D, and F. Although it is possible to select and use two or more types, there is almost no significant difference in the properties of the resulting thin film, and the disadvantages are far greater, such as increased costs due to complication of the process.

Further, from Group B, one type or two or more types may be selected. When selecting two or more types, those with different metal elements are selected. In this case, mixed crystal ferrite is obtained.

Furthermore, no matter which compound is selected from Groups A, B, D, and E, there is almost no significant difference in the properties of the resulting thin films. That is, there is almost no significant difference in the properties of the resulting thin film due to differences in alkoxy groups or alkoxyalkoxy groups.

Although the mixing ratio of the compounds of each group A, B, D, and E varies somewhat depending on their type, the compound of group A is mixed with a mole of
When the compound of group B is b mol, the compound of group 0 is d mol, and the compound of group E is e liter, the formula is 0.1 (a + b)≦d≦3 (a+b)0.01≦[
It is preferable that the range satisfies (a+b)/e]≦3 at the same time.

That is, when d<0.1 (a + b), it may not be possible to sufficiently suppress the hydrolysis of the compounds of each group A and B.
When d>3 (a and b), the viscosity of the mixed solution may become too high to form a film.

Further, when [(a+b)/e] <0.01, the amount of solvent is too large to be practical. Zarani, [(a0b)/el>3
In this case, compounds of each group A and B may remain dissolved.

The mixing operation may be performed by adding and mixing the compounds of each ASB group to a mixed solution of the compounds of group 0 and the compound of group E. Note that until the mixing operation is completed, it is preferable to avoid exposing the compounds of each group A and B to moisture as much as possible, and it is preferable to carry out the mixing in a glove box purged with dry nitrogen, etc.
Further operations can be carried out in air.

Step of forming a thin film of the mixed solution: In the first method, next, a thin film of the mixed solution is formed on the heat-resistant substrate. In other words, a film is formed.

The substrate may be of any type as long as it can withstand the firing temperature described below.
Metals such as gold, silver, platinum, alloys containing at least one of these metals as a main component, glass, carbon, silicon, silica, alumina, magnesia, zirconia, strontium titanate, titania, boron nitride, silicon nitride Free materials such as , boron carbide, silicon carbide, etc. can be used. The shape may be fibrous, film, plate, bulk, or the like. It is preferable that the surfaces of these substrates be polished to make them smooth or washed to remove dirt caused by oil or the like.

The thin film can be formed by applying with a brush, roller, etc., by spraying, or by a dip coating method in which the substrate is immersed in a mixed solution and then pulled up. Among these, the dip coating method is preferred because it is relatively simple and allows the film thickness to be changed by changing the pulling speed.

Drying step: In the first method, the thin film formed on the substrate is then dried to evaporate the compounds of group E, that is, the solvent, to form A and B.
, D is a gelled thin film consisting of compounds of each group. This step may be performed at room temperature or at a constant temperature of about 50 to 100°C.

Firing step: In the first method, the dried thin film is then fired together with the substrate in an oxidizing atmosphere to decompose and evaporate the organic components and oxidize the compounds of each ASB group. Then,
The spinel type ferrite thin film described above is obtained. This firing is performed, for example, as follows.

That is, the thin film is placed together with the substrate in a heating furnace, heated to a firing temperature in an oxidizing atmosphere, held at that temperature for a certain period of time, and then cooled to room temperature. The firing atmosphere is air or 20~
The concentration of oxygen is 100%. The temperature increase rate is preferably 1 to b. If it is less than 1° C./min, it takes too long to raise the temperature and is not practical. If the temperature exceeds 1000° C./min, cracks may occur in the thin film. Firing temperature is 350-120
Preferably it is 0°C. If the temperature is less than 350°C, the organic components in the thin film may remain, and if it exceeds 1200°C, the thin film may partially dissolve or evaporate. The baking time is
It may take from several tens of minutes to several hours. The cooling rate is also preferably 1 to 1000'C/min for the same reason as in the case of temperature increase.

Above, the first method was explained, but the second method
This method is basically the same as the first method.

That is, regarding the mixed solution preparation step, instead of the compound of group B in the first method, a compound of group 0, that is,
The only difference is that methoxide, ethoxide, propoxide, butoxide, methoxyethoxide or ethoxyethoxide of Ba, Sr, Pb is used.

However, in the second method, co, Ni.

Mn, Zn, Ca, Ti, In, Nb, la.

It can be modified with Ce, l)r, 3m, etc., in which case it is added in the form of methoxide, ethoxide, propoxide, butoxide, methoxyethoxide or ethoxyethoxide during the preparation of the mixed solution. During addition,
It may be about 1 to 15 mol% based on Fe.

(Example) Example 1 In a glove box flowing dry nitrogen, 0.02 mol of Fe methoxide and 0.01 mol of Ni methoxide were measured, and 0.03 mol of monoethanolamine was added thereto. Then, 100ml of methanol was added to the colander and stirred for 30 minutes using Star 9 to obtain a mixed solution.

On the other hand, a quartz glass plate with a thickness of 1 mm was ultrasonically cleaned using trichlorethylene, acetone, ethanol, and pure water for 3 minutes each, and then dried by spraying with high-purity dry nitrogen.

Next, the quartz glass plate was immersed in the mixed solution, and after 1 minute, was pulled up vertically at a speed of 10 cm/min to form a thin film of the mixed solution on the quartz glass plate.

Next, the thin film was dried for 30 minutes in a constant temperature bath at 50°C.

Next, the dried thin film was placed in an electric furnace together with the quartz glass plate, heated to 700°C at a rate of 10°C/min, held at that temperature for 2 hours, and then cooled to room temperature at a rate of 50°C/min. did.

When the thin film obtained in this way was analyzed by elemental analysis and X-ray diffraction, it was found that the thin film was embedded in the Ni-ferrite 1, which is NiFe2O4, and was extremely homogeneous, with no foreign matter or cracks observed even when observed under a microscope at 600x magnification. I failed.

Example 2 In a glove box flowing dry nitrogen, 0.02 mol of Fe ethoxide and 0.01 mol of Ni ethoxide were weighed out, 0.03 mol of jetanolamine was added thereto, and ethanol was added. 100m1 plus star 9
The mixture was stirred for 30 minutes to obtain a mixed solution. Thereafter, in the same manner as in Example 1, a thin film was obtained on a quartz glass plate.

This thin film was also a Ni-ferrite thin film of NiFe2O4, and like the one obtained in Example 1, it was extremely homogeneous.

Example 3 In a glove box flowing dry nitrogen, 0.02 mol of Fe ethoxide and 0.01 mol of Go ethoxide were weighed out, 0.03 mol of jetanolamine was added thereto, and ethanol was added. 100m1 plus star 9
The mixture was stirred for 30 minutes to obtain a mixed solution. Thereafter, in the same manner as in Example 1, a thin film was obtained on a quartz glass plate.

This thin film was a Go-71 light thin film of C0Fe2O4, and similar to that obtained in Example 1, it was extremely homogeneous.

Example 4 In a glove box flowing dry nitrogen, 0.02 mol of Fe ethoxide and 0.01 mol of Zn ethoxide were weighed out, 0.03 mol of jetanolamine was added thereto, and ethanol was added to the solution. Add 100m1, star 9
The mixture was stirred for 30 minutes to obtain a mixed solution. Thereafter, in the same manner as in Example 1, a thin film was obtained on a quartz glass plate.

This thin film was a zn-ferrite thin film of 7nFe204, and similar to that obtained in Example 1, it was extremely homogeneous.

Example 5 In a glove box flowing dry nitrogen, 0.02 mol of Fe ethoxide and 0.01 mol of Mn ethoxide were weighed out, 0.03 mol of jetanolamine was added thereto, and ethanol was added. 100m1 plus star 9
The mixture was stirred for 30 minutes to obtain a mixed solution. Thereafter, in the same manner as in Example 1, a thin film was obtained on a quartz glass plate.

This thin film was a Mn-ferrite thin film called MnFe20q, and like the one obtained in Example 1, it was extremely homogeneous and solid.

Example 6 In a glove box flowing dry nitrogen, 0.02 mol of Fe ethoxide and 0.005 mol of Ni ethoxide were added.
0.01 mole of ethoxide in mole, zn was weighed out, 0.03 mole of jetanolamine was added thereto, 100 ml of ethanol was added, and the mixture was stirred for 30 minutes using Star 9 to thaw the mixed solution. Hereinafter, in the same manner as in Example 1,
A thin film was obtained on a quartz glass plate.

This thin film has N l □, 5 Z I'l □, 5 F
It was a Nr-2n ferrite thin film called C204, and was extremely homogeneous, similar to the one obtained in Example 1.

Example 7 In a glove box flowing dry nitrogen, 0.02 mol of Fe ethoxide and 0.005 mol of Mn ethoxide were added.
0.01 mole of ethoxide in mole, zn was weighed out, 0.03 mole of jetanolamine was added thereto, 100 ml of ethanol was further added, and the mixture was stirred for 30 minutes using a Stark shaker to obtain a mixed solution. Hereinafter, in the same manner as in Example 1,
A thin film was obtained on a quartz glass plate.

This thin film consists of Mn05Zno,5Fe2O4
It was an n-2n ferrite thin film, and similar to that obtained in Example 1, it was extremely homogeneous.

Example 8 In a glove box flowing dry nitrogen, 0.012 mol of Fe methoxide and 0.00 mol of Ba methoxide were added.
Measure out 1 mole and add 0.0 of monoethanolamine to it.
Add 15 mol, add 100ml of methanol to the colander,
The mixture was stirred for 30 minutes using a Stark shaker to obtain a mixed solution.

On the other hand, a quartz glass plate with a thickness of 1 mm was ultrasonically cleaned using trichlorethylene, acetone, ethanol, and pure water for 3 minutes each, and then dried by spraying with high-purity dry nitrogen.

Next, the quartz glass plate was immersed in the mixed solution, and after 1 minute, was pulled up vertically at a speed of 10 cm/min to form a thin film of the mixed solution on the quartz glass plate.

Next, the thin film was dried in a constant temperature bath at 50'C for 30 minutes.

Next, the dried thin film was placed in an electric furnace together with the quartz glass plate, and the temperature was raised to 850°C at a rate of 10°C/min. After holding at that temperature for 2 hours, the temperature was raised to room temperature at a rate of 50°C/min. Cooled.

When the thin film thus obtained was analyzed by elemental analysis and X-ray diffraction, it was found to be a magnetobrambite-type Ba-hexaferrite thin film called BaFe12O19, and no foreign matter or cracks were observed even when observed under a microscope at 600x magnification. , was extremely homogeneous.

Example 9 In a glove box flowing with dry nitrogen, 0.012 mol of Fe methoxide and 0.00 mol of 3r methoxide were added.
Measure out 1 mole and add 0.0 of monoethanolamine to it.
Add 15 mol and further add 100 ml of methanol,
The mixture was stirred for 30 minutes using a Stark shaker to obtain a mixed solution. Thereafter, in the same manner as in Example 8, a thin film was obtained on a quartz glass plate.

This thin film was S r Fe 12019, magnetobrambite type 3r-hexaferrite 1111, and was extremely homogeneous, similar to that obtained in Example 8.

Example 10 In a glove box flowing with dry nitrogen, 0.012 mol of Fe methoxide and 0.00 mol of Pb methoxide were added.
Measure out 1 mole and add 0.0 of monoethanolamine to it.
Add 15 mol and further add 100 ml of methanol,
The mixture was stirred for 30 minutes using a Stark shaker to obtain a mixed solution. Thereafter, in the same manner as in Example 8, a thin film was obtained on a quartz glass plate.

This thin film was a magnetobrambite-type Pb-hexaferrite thin film containing 1201 g of PbFe, and was extremely homogeneous like that obtained in Example 8.

Example 11 In a glove box flowing dry nitrogen, 0.012 mol of Fe ethoxide and 0.00 mol of 3a ethoxide
Measure out 1 mole and add 0.01 jetanolamine to it.
5 mol was added, 100 ml of ethanol was added to the colander, and the mixture was stirred for 30 minutes using a Stark shaker to obtain a mixed solution. below,
A thin film was obtained on a quartz glass plate in the same manner as in Example 8.

This thin film was a magnetobrambite type 3a-hexaferrite thin film called B a Fe 12019, and like the one obtained in Example 8, it was extremely homogeneous.

Example 11 In a glove box flowing dry nitrogen, 0.011 mol of Fe ethoxide and 0.00 mol of Ba ethoxide were added.
Weigh out 1 mol of Co ethoxide, 0.0005 mol of Co ethoxide, and 0.0005 mol of Li ethoxide, add O0015 mol of jetanolamine thereto, further add 100 ml of ethanol, and stir for 30 minutes using a Stark shaker.
A mixed solution was obtained.

On the other hand, a quartz glass plate with a thickness of 1 mm was ultrasonically cleaned using trichlorethylene, acetone, ethanol, and pure water for 3 minutes each, and then dried by spraying with high-purity dry nitrogen.

Next, the quartz glass plate was immersed in the mixed solution, and after 1 minute, was pulled up vertically at a speed of 10 cm/min to form a thin film of the mixed solution on the quartz glass plate.

Next, the thin film was dried for 30 minutes in a constant temperature bath at 50°C.

Next, the dried thin film was placed in an electric furnace together with the quartz glass plate, and the temperature was raised to 850'C at a rate of 10°C/min. Cooled to warm temperature.

When the thin film thus obtained was analyzed by elemental analysis and X-ray diffraction, it was found that B a Fe 11c Oo, sT
' 0.5019 magnetobrambite type Ba-
It was a hexaferrite thin film, and was extremely homogeneous with no foreign matter or cracks observed even by FA inspection using a microscope with a magnification of 600 times.

(Effects of the Invention) This invention forms a thin film on a heat-resistant substrate from a mixed solution all at once while suppressing the hydrolysis of compounds of groups A, B, and C using a compound of group D, and dries the film in an oxidizing atmosphere. Since the ferrite film is converted into a ferrite thin film by firing inside, a ferrite thin film with excellent homogeneity can be easily obtained as shown in the examples.

Claims (1)

[Scope of Claims] (a) Among the compounds of Group A, Group B, Group C, Group D and Group E below, Group A, Group B, Group D and Group E, or Group A, Group C, A step of preparing a mixed solution containing a compound selected from Group D and Group E, Group A: Fe, methoxide, ethoxide, propoxide, butoxide, methoxyethoxide or ethoxyethoxide Group B: Co, Ni, Zn, Mn, Cu, Li, Mg, A
l, Cr, V, Sb, Mo, Ti, Sn, methoxide, ethoxide, propoxide, butoxide, methoxyethoxide or ethoxyethoxide Group C: Ba, Sr, Pb, methoxide, ethoxide,
Propoxide, butoxide, methoxyethoxide or ethoxyethoxide group D: monoethanolamine, diethanolamine, triethanolamine, mono-2-propanolamine, di-2-propanolamine, acetylacetone, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol Group E: methanol, ethanol, propanol, butanol, methoxyethanol, ethoxyethanol (b) forming a thin film of the above mixed solution on a heat-resistant substrate; (c) drying the thin film; (d) the above. A method for forming a ferrite thin film, comprising the steps of: converting a dry thin film into a ferrite thin film by firing the dry thin film in an oxidizing atmosphere.